Cable guiding in wind turbine towers

Abstract

The present disclosure relates to towers for wind turbines comprising a top section supporting a nacelle about a yaw axis, wherein the nacelle comprises an electric power component and a power cable for electrically connecting the electric power component to an electrical connection point in a lower section of the tower. The power cable extends downwards from the nacelle to a first height along a substantially central area of the tower, and at a first height the power cable comprises a power cable loop. The power cable loop includes an upwards curve, and a downwards curve. The power cable loop comprises a movable cable part, and a fixed cable part, and the fixed cable part comprises at least a portion of the downwards curve. The present disclosure further relates to wind turbines and to methods for arranging cables in wind turbine towers.

The invention claimed is: 
     
       1. A tower for a wind turbine, comprising:
 a top section supporting a nacelle of the wind turbine about a yaw axis, wherein the nacelle comprises an electric power component; 
 a power cable electrically connecting the electric power component to an electrical connection point in a lower section of the tower; 
 the power cable extending downwards from the nacelle along a substantially central area of the tower, wherein at a first height between the nacelle and the electrical connection point, the power cable comprises a power cable loop that includes an upwards curve and a downwards curve; 
 the power cable loop comprising a movable cable part, and a fixed cable part, wherein the fixed cable part comprises at least a portion of the downwards curve; 
 the fixed cable part comprising an upwards portion and a downwards portion; and 
 wherein the upwards portion and the downwards portion of the fixed cable part are attached to an inner wall surface of the tower so as to extend along the inner wall surface of the tower. 
 
     
     
       2. The tower of  claim 1 , wherein the movable cable part comprises a movable upwards portion, and the fixed cable part extends from an end of the movable cable loop. 
     
     
       3. The tower of  claim 1 , wherein the movable cable part extends substantially in a vertical longitudinal plane of the tower. 
     
     
       4. The tower of  claim 1 , wherein the first height is determined such that the power cable arranged between the nacelle and the first height is configured to absorb a maximum amount of yaw of the nacelle in a single direction. 
     
     
       5. The tower of  claim 1 , further comprising a platform proximate the first height, the downwards portion of the fixed cable part attached to the inner wall surface of the tower above and below the platform. 
     
     
       6. The tower of  claim 1 , wherein the electric power component is a main transformer of the wind turbine. 
     
     
       7. The tower of  claim 1 , further comprising a plurality of auxiliary cables extending between the nacelle and a lower section of the tower, and further comprising cable guiding assemblies that guide the power cable and the auxiliary cables. 
     
     
       8. The tower of  claim 7 , wherein the auxiliary cables include electrical cables for power supply to auxiliary systems of the wind turbine or communication cables. 
     
     
       9. The tower of  claim 7 , wherein the power cable is arranged in a central through-hole of the cable guiding assemblies. 
     
     
       10. A method for guiding a power cable in a wind turbine, comprising:
 connecting the power cable to an electrical power component in a nacelle of the wind turbine; 
 arranging the power cable through a central area of a bottom of the nacelle such that the power cable extends substantially vertically downwards from the nacelle to a first height along a central area of a tower; 
 directing the power cable from the central area of the tower through a platform and to an inside wall of the tower proximate the first height; 
 attaching the power cable to the inside wall of the tower above and below the platform such that a substantially vertical loop is formed in the power cable. 
 
     
     
       11. The method of  claim 10 , further comprising arranging auxiliary cables substantially in parallel with the power cable along the central area of the tower, and guiding the power cable and the auxiliary cables in a cable guiding assembly. 
     
     
       12. A method for guiding a power cable in a wind turbine, comprising:
 connecting the power cable to an electrical power component in a nacelle of the wind turbine; 
 arranging the power cable through a central area of a bottom of the nacelle such that the power cable extends substantially vertically downwards from the nacelle to a first height along a central area of a tower; 
 directing the power cable from the central area of the tower to an inside wall of the tower proximate the first height; 
 attaching the power cable to an inside of a wall of the tower forming a substantially vertical loop; 
 arranging auxiliary cables substantially in parallel with the power cable along the central area of the tower, and guiding the power cable and the auxiliary cables in a cable guiding assembly; and 
 wherein proximate the first height, the auxiliary cables include an auxiliary cables loop, wherein the auxiliary cables loop is arranged separately from the power cable loop. 
 
     
     
       13. A wind turbine comprising:
 a wind turbine rotor including a plurality of rotor blades; 
 a generator operatively coupled to the wind turbine rotor for generating electrical power; 
 a power electronic converter configured to convert the electrical power generated by the generator to a converted AC power of predetermined frequency and voltage; 
 a main wind turbine transformer having a low voltage side and a high voltage side for transforming the converted AC power to a higher voltage; 
 a nacelle housing the generator, the power electronic converter, and the main transformer therein; 
 a tower, the nacelle rotatably supported on the tower; 
 a power cable electrically connecting the high voltage side of the main wind turbine transformer to an electrical connection point proximate a bottom section of the tower; 
 a platform at a fixed height within the tower; 
 wherein the power cable is arranged from the nacelle downwards along a central area of the tower through the platform, and wherein the power cable comprises a vertical power cable loop at the fixed height of the platform; 
 the power cable loop comprising a movable cable part, and a fixed cable part; and 
 the fixed cable part attached to an inner wall surface of the tower above and below the platform so as to extend along the inner wall surface of the tower. 
 
     
     
       14. The wind turbine of  claim 13 , wherein the power cable is configured to transmit electrical power of a voltage of 20 kV or more. 
     
     
       15. The wind turbine of  claim 13 , wherein a minimum bending radius of the power cable in the movable cable part is at least 0.7 meters. 
     
     
       16. The wind turbine of  claim 13 , wherein the fixed cable part is attached to the inner wall surface of the tower with brackets.